Electromagnetically-operated printer

ABSTRACT

An electromagnetically-operated printer comprising a type wheel comprising a plurality of wheels frictionally mounted on the shaft, means for printing the types on tye paper, type selecting means for selecting a given type for each of the columns of said type wheel, column selecting means rotating at a predetermined ratio relative to the shaft of said type wheel, said column selecting means being functionally coupled to said type selecting means, and electromagnetic means each corresponding to two or more columns in a group of said column selecting means and functionally coupled to said type selecting means. The wheel of each column is adapted to be positioned in different phase for adjacent columns and the column selecting means are adapted to actuate the printing means in the same phase difference of the types.

O United States Patent [1 1 [111 3,890,894 Nihira June 24, 1975 [54] ELECTROMAGNETICALLY-OPERATED 3,528,368 9/1970 Oberholzer et a1. l0l/93.31 X 3,738,264 6/1973 Sobottka et al 101/110 PRINTER 3 756147 9/1973 Gr t l lOl/llO X oss e a [75] Inventor: Shohachi Nihira, Tokyo, Jap 3,814,229 6/1974 Kohlhage 101/110 X [73] Assignee: Citizen Watch Company Limited,

Tokyo, Japan Przmary ExamznerE. H. Elckholt Attorney, Agent, or Firm-Dorfman, Herrell and [22] Filed: Aug. 15, 1974 skillman [21] Appl. No.: 497,562

Related US. Application Data [57] ABSTRACT [63] Continuation-impart of Ser. No. 356,472, May 2, e1ectromagneilfany'operatfad 's r a type wheel comprising a plurality of wheels frlctionally 1973, Pat. No. 3,848,527.

mounted on the shaft, means for printing the types on 0 F A P D ta tye paper, type selecting means for selecting a given [3 "on y a 47 44378 type for each of the columns of said type wheel, col- May apan umn selecting means rotating at a predetermined ratio relative to the shaft of said type wheel, said column [52] i l01/93'18 A 7g33 selecting means being functionally coupled to said 2; 'i 18 21 type selecting means, and electromagnetic means each 1 le 6 93 29 corresponding to two or more columns in a group of g said column selecting means and functionally coupled to said type selecting means. The wheel of each column is adapted to be positioned in different phase for [56] References cued adjacent columns and the column selecting means are UNITED STATES PATENTS adapted to actuate the printing means in the same 3,141,403 7/1964 Brown et a1. 101/99 phase difference of the types. 3,420,164 l/l969 Lee lOl/93.29 3,422,754 1/1969 Bakardjiev et a1 101/99 x 1 Claim, 2 Drawmg Flgures I O I! ELECTROMAGNETICALLY-OPERATED PRINTER This application is a continuation-in-part of application of Ser. No. 356,472, filed May 2, 1973 and now US. Pat. No. 3,848,527.

This invention relates to an electromagneticallyoperated printer and, more particularly, to printer having selecting means to select given types or type characters from a rotating type wheel.

There has heretofore been known in the art a number printer, which uses electromagnetic hammers each having a head spreading plural columns of a type wheel. Digits or types of each column are disposed in different phase with types of adjacent column in order to print one digit at one printing action and in which the electromagnetic hammers are driven a plurality of times to perform printing of one line.

This type of the system can hardly be employed for the simultaneous printing of all digits of one line.

An object of the present invention is to provide a printing which can be used for simultaneous printing.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a fragmentary perspective view showing one embodiment of the present invention; and

FIG. 2 is a side view of the same.

Referring to the drawings, numeral 31 designates a rotary shaft, which is coupled to a shaft of select roll 32 through gear means (not shown) so as to rotate the select roll in the same direction. The select roll 32 completes one rotation for the one pitch movement of the type wheel 33. The select roll 32 has one projection 32a for individual columns, and adjacent columns are shifted by 120 degrees.

The type wheel 33 comprises independent wheels for individual columns. These wheels have hooks 33a and types 33b spaced at same pitch. Also, the wheels are provided with reset ends 33c located at different phase for the individual columns and are frictionally coupled to the rotary shaft 31. Further, select pawls 34 are provided for the individual columns and biased with springs 35 such that they will be engaged with a hook 33a of type wheel 33. Each select pawl 34 has a hook 34a engaging with the corresponding end 36a of an associated trigger lever 36. The trigger lever has a notch 36b at the other end, with which an armature is engaged. Each trigger lever 36 has a central slot 36c extending in a direction at right angles to its longitudinal direction. A trigger lever guide 37 extending parallel to the rotary shaft 31 engages with slots 36c to prevent the movement of the trigger levers 36. Each trigger lever 36 is biased clockwise by a trigger lever spring 38 so that end 36a is engaged with the hook 34a of the associated select pawl 34. Numeral 39 designates a select pawl guide having a reset edge 3911 which engages with reset ends 33c. An electromagnet associated with the armature 10 is provided for three adjacent trigger levers 36 for three adjacent columns. The armature of each group is rotatably mounted on an armature shaft 11 and biased downward by an armature spring 13 hooked at one end of magnet support plate 12. Three columns in one group are constituted by the three different type wheels. The three type wheels are arranged such that phase difference between types 33b is onethird of the type pitch. This corresponds to the phase difference of the projections 32a of the select roll 32.

The rotary shaft 31 is driven by a drive means (not shown) to make a reciprocal turn within about in one line printing period. Numeral 40 designates a platen which is interlocked to the afore-mentioned drive means to execute one reciprocation against the type wheel 33. Numeral 41 designates a pawl clear bar also interlocked to the afore-mentioned drive means to cause rotation of the select pawls 34.

In operation, when the drive means is operated in response to a print command, the rotary shaft 31 is rotated from the illustrated position in the clockwise direction and the type wheel 33 is rotated in the clockwise direction, and also the select roll 32 is rotated in the same direction. I

In course of this rotation, when a given type of a given column comes to the engaging position with respect to the select pawls 34 and the corresponding projection 32a of the select 'roll 32 comes to face the corresponding trigger lever 36, a suitable printer control circuit energizes the corresponding electromagnet 20 to attract the associated armature 10. As a result, the three trigger levers 36 engaged by the armature are activated. However, in other columns than the given one the projections 32a of the select roll 32 are not positioned to face the respective trigger levers 36, so that these trigger levers 36 merely swing about their end 36a and do not detach from the associated select pawls 34. On the other hand, the trigger lever 36 for the given column rotates about the projection 32a of the select roll 32, so that its end 36a detaches from the hook 34a of the associated select pawl 34. As a result, the select pawl 34 of the given column is rotated by the associated spring 35 in the counterclockwise direction to be engaged with the hook 33a of the type wheel 33 of the given column. Thus, the type wheel 33 is locked by the pawl and consequently slips on the rotary shaft 31 and thereby holding the given type in the position to face the platen 40. This sequence of actions takes place for each column, so that given types of given columns are all held in position to face the platen 40. In this way, the type select operation is completed. Thereafter, at the end of the forward stroke of the rotary shaft 31 the afore-mentioned urging action of the platen 40 is caused by the drive means to effect printing on the recording sheet 22.

Subsequent to the printing, the platen 40 is retreated, while at the same time the pawl clear bar 41 is moved toward the select pawls 34- to return the select pawls 34 to the initial position, whereby the trigger levers 30 are engaged by the hooks 34a of the returned select pawls 31 to recover the initial state. Subsequently, the clear bar 41 is returned to the initial position, whereupon the rotary shaft 31 rotates in the opposite direction, that is, in the counterclockwise direction. Following this, the type wheel 33 is rotated in the counterclockwise direction until its reset end 330 abuts to the reset edge 39a of the select pawl guide 39 and is held in the initial position. Concurrently, the ink ribbon 21 and recording sheet 22 are appropriately fed by the sheet feed roller 23, thus printing operation for one line is completed.

While the preceding embodiment has a construction where the type wheel is frictionally coupled, it will be apparent that the invention can also be effectively applied to the well-known simultaneous line printing system having a type wheel rotated by a built-in spiral spring in one direction and also in the well-known simultaneous line printing system where select pawls are coupled to a reciprocating sector gear.

What is claimed is:

1. An electromagnetically-operated printer for printing on paper comprising a type wheel which comprises a plurality of column wheels frictionally mounted on a shaft in groups, each column wheel having types, hooks and a projection operative as a reset edge, means for printing the types on the paper, stopping means for engaging with said projections of all of the column wheels, said types being so arranged that when all column wheels are stopped by said stopping means, the wheels in each group are positioned in different phases, a select pawl provided for each column wheel and adapted to engage with said hooks of each column wheel, type selecting means for selecting a given type for each of the column wheels of said type wheel, column selecting means for each group of wheels rotating at a predetermined ratio relative to the shaft of said type wheel, said column selecting means being functionally coupled to said type selecting means, and electromagnetic means each corresponding to said column selecting means and functionally coupled to said type selecting means, said electromagnetic means being controlled by an electrical control means for comparing a given type with the type position of said type wheel, and said type selecting means being actuated only when both said column selecting means and said electromagnetic means are simultaneously actuated.

l l l l 

1. An electromagnetically-operated printer for printing on paper comprising a type wheel which comprises a plurality of column wheels frictionally mounted on a shaft in groups, each column wheel having types, hooks and a projection operative as a reset edge, means for printing the types on the paper, stopping means for engaging with said projections of all of the column wheels, said types being so arranged that when all column wheels are stopped by said stopping means, the wheels in each group are positioned in different phases, a select pawl provided for each column wheel and adapted to engage with said hooks of each column wheel, type selecting means for selecting a given type for each of the column wheels of said type wheel, column selecting means for each group of wheels rotating at a predetermined ratio relative to the shaft of said type wheel, said column selecting means being functionally coupled to said type selecting means, and electromagnetic means each corresponding to said column selecting means and functionally coupled to said type selecting means, said electromagnetic means being controlled by an electrical control means for comparing a given type with the type position of said type wheel, and said type selecting means being actuated only when both said column selecting means and said electromagnetic means are simultaneously actuated. 